When I was 10 years younger I could pull the cab and have the transmission on the ground in 6 hours on non PTO tractors a little longer for three point and PTO tractors. A complete disassemble of the transmission was 8 hours if you took your time and laid all the part out on a big clean table. To put the transmission back took a good 20 hours because adjusting the bearing  takes a lot of time .About 8 hours to put it back in and the cab on. This is in a shop with a overhead hoist .